Answer:
One adult ticket is $4 and one child ticket is $7
Explanation:
Make a system of equations
2x + 10y = 78
8x + 5y = 67
Solve by elimination, multiply the 2nd equation by -2
2x +10y = 78
-16x -10y = -134
Add the equations
-14x = -56
x = 4
The price of one adult ticket is $4
Plug 4 in as x to find y
2(4) + 10y = 78
8 + 10y = 78
10y = 70
y = 7
The price of one child ticket is $7